JPH1164202A - Method and device for testing shear strength - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the shear strength of soil in slaking state generated by repeated drying/wetting. SOLUTION: An air inlet 13, an air outlet 17, and water inlet/outlet 12 are provided to an environment condition setting vessel 10, where a specimen housing vessel 20 is provided. The specimen housing vessel is provided with a pressurizing means 60 such that a stress is applied from below in vertical direction and in one horizontal direction orthogonal to it. A displacement constraining means 30 is provided horizontally, orthogonal to the pressurizing means. A soil investigation sample is put in the specimen housing vessel 20, and a stress is applied after compaction, which is to be a specimen, then the specimen is dried and wetted repeatedly for generating slaking, and a maximum main stress is applied vertically from above under the condition, for plane strain shear strength test.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a strength test technique for determining the shear strength of soil, such as an embankment material made of soft rocks, which softens due to slaking due to repeated wet and dry.

[0002]

2. Description of the Related Art When soft rocks such as mudstone, shale, tuff, sandstone, etc. are cut and buried, embankment is stable at the beginning of the embankment, but slaking occurs due to repeated dry and wet after a long period of time and softens.

[0003] The strength of the embankment material composed of soft rocks is a value obtained when the embankment is softened due to repeated wet and dry conditions after embankment (mainly a dry condition due to clear weather and a wet condition due to rainfall or rising groundwater level). Need to ask.

Conventionally, as a technique of soil testing in such a slaking state, the development and commercialization of a test apparatus capable of determining the compression settling characteristics have been known.

[0005]

SUMMARY OF THE INVENTION Mudstone, shale, tuff,
When embankment is made with a material obtained by cutting the ground made of soft rocks such as sandstone, the embankment is stable at the beginning of embankment, but softens due to repeated drying and wetness received for a long time afterwards.
Large subsidence occurs on the embankment, or slippage occurs on the embankment slope due to reduced strength.

[0006] Therefore, in the investigation of soil properties such as embankment in which such slaking occurs, it is necessary to investigate both characteristics of compression settlement and strength.

[0007] However, although a test technique for examining compression settling characteristics in a slaking state has been conventionally known,
The technology for strength property testing has not yet been developed.

[0008] It is an object of the present invention to obtain the shear strength of soil in a slaking state generated by repeated wet and dry.

The above and other objects and novel features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

[0010]

SUMMARY OF THE INVENTION Among the inventions disclosed in the present application, the outline of a representative one will be briefly described.
It is as follows.

For example, an embankment material obtained by cutting a ground made of soft rocks is put into a specimen storage container formed in a cubic shape or a rectangular parallelepiped shape as a soil investigation sample.

[0012] Thereafter, the embankment material of the soil investigation sample placed in the specimen storage container is compacted by a compaction machine such as a rammer or a vibrator under the same water-containing condition as when embankment is performed, to produce a specimen.

[0013] Further, stress is applied by pressing independently from three axial directions perpendicular to each other by pressing means such as cylinder compression or the like, and conditions are set in accordance with the stress state in the embankment slope or ground.

In order to apply the stress by the pressing means independently from the three axial directions, for example, the maximum principal stress (σ ₁ ) Add. At the same time, the minimum principal stress (σ ₃ ) is independently added from the horizontal direction orthogonal to the maximum principal stress (σ ₁ ) direction, and conditions are set in accordance with the embankment slope and the stress state in the ground.

[0015] A test piece having such stress conditions set therein is:
Slaking is generated by performing dry and wet cycles. The repetition of the wet and dry may be performed as follows.

The inside of the environment condition setting container in which the specimen storage container is provided is made into a dry environment by the drying means, and the specimen in which the above-mentioned stress condition is set is brought into a dry state through the inside / outside communication part provided in the specimen storage container. I do.

As the drying means, for example, an intake port and an exhaust port are provided in the environmental condition setting container, and the air intake port is connected to an external hot air generator so that the predetermined temperature is set in the environmental condition setting container. Send the set hot air for a certain period of time. The sent hot air is allowed to escape from the exhaust port so that the hot air passes through the environmental condition setting container. In this way,
The environment condition setting container can be set in a dry environment.

As described above, in the specimen storage container placed in the environmental condition setting container in a dry environment, the specimen is brought into a dry state by coming into contact with hot air through the inside / outside communication part. The water vapor generated at the time of drying the specimen is exhausted to the outside of the environmental condition setting container together with the hot air, so that the drying environment in the environmental condition setting container can be maintained.

On the other hand, the wet state of the specimen is performed as follows.

The environment condition setting container in which the specimen storage container is provided is made humidified by the humidifying means, and the specimen in which the above-mentioned stress condition is set is brought into a wet state through the inside / outside communication part provided in the specimen storage container. I do.

As the humidifying means, for example, a water supply port is provided in the environmental condition setting container, and the water supply port is connected to an external faucet or the like, and water is sent into the environmental condition setting container. The water may be sent to such an extent that the specimen storage container is submerged.
In this way, the specimen storage container can be submerged for a certain period of time in the environmental condition setting container and placed in a humid environment.

As described above, in the specimen storage container placed in the environmental condition setting container in a humid environment caused by submergence, the specimen is absorbed by the water via the internal / external communication part and is brought into a wet state. When the specimen becomes sufficiently wet, drain the water contained in the environmental condition setting container from the drain port.

By alternately repeating the drying means and the humidifying means a predetermined number of times, the sample is repeatedly dried and wet to generate slaking. In this way,
The strength test may be performed in a state where slaking has occurred in the test specimen.

In the strength test, for example, only the maximum principal stress (σ ₁ ) is increased on the specimen having the slaking as described above, and the measurement is performed by the measuring means linked to the pressing means having the above configuration. The shear strength of the specimen may be determined based on the value.

[0025]

Embodiments of the present invention will be described below in detail with reference to the drawings.

(Embodiment 1) In this embodiment, a description will be given of a shear strength test apparatus having a configuration in which the displacement of a specimen in a horizontal direction is restricted so that a plane strain shear strength test can be performed.

FIG. 1 shows a shear strength test apparatus having such a configuration.
As shown in (1), the specimen storage container 20 is installed in the environmental condition setting container 10, and stress is applied to the soil investigation sample placed in the specimen storage container 20, or the wet and dry operation is repeated. , So that a shear strength test can be performed under conditions of occurrence of slaking.

The environmental condition setting container 10 according to the present embodiment
As shown in FIGS. 1 and 2, it is formed in a substantially cylindrical shape, and a circular bottom portion 11 is provided with a supply / drain port 12.
The supply / drainage port 12 is formed as a bent short pipe connection port 12a.

The bottom portion 11 is provided with an environmental condition setting container 10.
Is slightly raised from the installation surface S, and is formed in a thick part with a heavy weight. By forming the thick part with a heavy weight, as described later, the maximum principal stress (σ
_{Even when 1} ) is applied vertically downward, the entire device can be stabilized.

The bottom portion 21 of the specimen storage container 20 is fixed on the bottom 11, and the specimen storage container 20 is provided in the environmental condition setting container 10. The bottom portion 21 is formed to have a thickness slightly rising from the bottom surface 11a of the environmental condition setting container 10, and is set so that the top surface (corresponding to the bottom surface 21a) is a planar square shape.

A porous member 22a is provided at the center of the flat portion of the bottom portion 21 so as to be flush with the bottom surface 21a. In this embodiment, a grindstone is used as the porous member 22a. In addition, a member such as a porous plate having a large number of holes through which water and air can appropriately pass may be used.

A through hole 22b is formed on the bottom surface of the porous member 22a from the rising side surface of the bottom portion 21 to form an inner / outer communication portion 22 as a whole.

As will be described in detail later, the internal / external communication part 22 is provided so that the environmental conditions in the environmental condition setting container 10 can be exerted on the specimen side in the specimen storage container 20.

As shown in FIG. 2, the four directions of the bottom 21 are aligned with the four square side plates 23a, 23a ', 23b, 23b'.
A sample storage container 20 of an assembling type is provided so as to surround the container. In the present embodiment, the side plate 23
a and the side plate 23a 'and the side plate 23b and the side plate 23b' are provided on the sides facing each other, and the side plate 23a (or 23
a ') and the side plate 23b (or 23b') are provided on mutually orthogonal sides.

Side plates 23a, 23a ', 23b, 23
As shown in FIG. 2, b ′ and the bottom 21 are configured to be assembled in a box shape by screwing each end side with a screw N.

In particular, in the present embodiment, as shown in FIG. 3, both ends of the side plate 23b '(not shown, but the same applies to 23b) are provided with recesses according to the width of the end surfaces of the side plates 23a, 23a'. 23c is provided, and the end faces of the side plates 23a, 23a 'are screwed with screws N in a state where the end faces of the side plates 23a, 23a' are brought into contact with the assembling recess 23c.

By assembling in this manner,
Specimen storage container 2 when water submerged
0 or the soil investigation sample does not escape from the specimen storage container 20.

As shown in FIG. 2, the side plate 23a has an opening 24a for a displacement restricting means 30 for restricting the lateral displacement of the side surface of the specimen storage container 20 in the horizontal direction.
Is provided.

The displacement restricting means 30 is provided with a specimen restricting plate 33 at the tip end of a shaft 32 connected to the displacement restricting device 31 in the horizontal direction.
In a state in which it is moved back and forth to an appropriate position by hydraulic pressure while being supported by 2a, it can be restrained so as not to move (do not displace) against the pressure applied to the test piece restraining plate 33.

In the present embodiment, the back side of the test piece restraining plate 33 is planarly supported by a support plate 33a provided directly on the distal end side of the shaft 32, and a force is applied to the surface of the test piece restraining plate 33. The specimen restraining plate 3
It is configured such that the force applied to the test piece restraining plate 33 is transmitted in the direction of the shaft 32 without reducing the force applied to the specimen restraint plate 33 without wobbling.

Further, in this embodiment, the shaft 32
A load cell 40 a is provided as a measuring unit 40 between the displacement restraining device 31 and the displacement restricting device 31.

The opening 24a is formed in such a size that the support plate 33a can pass through so that the test sample restraining plate 33 can be fully pulled inside the side plate 23a.

The shaft 32 is inserted through the cylindrical side surface of the environmental condition setting container 10 so as to be able to enter and exit the environmental condition setting container 10 in a state where the shaft 32 is sealed so as not to cause water leakage. Have been. The guide bearing 32a is provided outside the cylindrical side surface through which the shaft 32 is inserted.

On the other hand, as shown in FIG. 2, the side plate 23b is provided with an opening 24b for the pressing means 50 for applying a stress from the horizontal direction of the specimen storage container 20.

The pressing means 50 is provided with a test piece pressing plate 53 on the tip side of a shaft 52 connected to a cylinder 51a constituting a horizontal loading device 51 in a horizontal direction.
The shaft 52 can be moved back and forth while being guided horizontally by a guide bearing 52a.

The forward and backward movement is performed by the horizontal loading device 51.
Can be moved back and forth while applying hydraulic pressure in either direction of both arrows a and b shown in the figure. In this way, the pressing means 50 can apply a stress from the horizontal direction of the side surface of the specimen.

In this embodiment, the back side of the specimen pressing plate 53 is planarly supported by a support plate 53a provided directly on the tip side of the shaft 52, and a force is applied from the back side of the specimen pressing plate 53. Even if it is applied, the specimen pressing plate 53 does not fluctuate on the distal end side of the shaft 52, and the force applied from the shaft 52 is transmitted to the specimen pressing plate 53 without being reduced.

In this embodiment, the specimen pressing plate 5
An appropriate amount of grease or the like is applied to the end face side of No. 3 so that sliding during operation can be performed smoothly. In the present embodiment, such a grease or the like is applied to the sliding portion so that smooth sliding can be appropriately secured without special description.

Further, in the present embodiment, the shaft 52
Between the load cell 40a and the horizontal loading device 51,
The displacement gauge 40b is provided as the measuring means 40.
A dial gauge or the like may be used for the displacement meter 40b.

The size of the opening 24b is determined by the test piece pressing plate 5
In order that the support plate 53a can pass through the inside of the side plate 23b, the support plate 53a may be opened to a size large enough to pass through.

Similarly to the displacement restraining means 30, the environmental condition setting container 1 is provided on the cylindrical side surface of the environmental condition setting container 10 with the shaft 52 being sealed in a watertight manner around the shaft 52.
It is inserted so that it can enter and exit inside 0.
The guide bearing 52a is provided on the outside of the side surface of the cylinder through which the shaft 52 is inserted.

Further, as shown in FIG. 1, an intake port 13 is opened at the bottom of the cylindrical side surface of the environmental condition setting container 10.

The intake port 13 has a connection nozzle 13a protruding toward the outside of the cylindrical side surface, and the connection nozzle 13a and a hot air generator (not shown) are connected by a heat-insulating flexible pipe 14, Hot air can be sent into the environmental condition setting container 10.

Further, the opening end face of the connection nozzle 13a can be appropriately closed by the lid 15 when the supply of hot air from the hot air generator is stopped and water is poured into the environmental condition setting container 10, as described later. It has become.

The circular opening above the environmental condition setting container 10 can be closed by a lid 16 as shown in FIG. The lid 16 is provided with a temperature sensor insertion hole so that the temperature inside the environmental condition setting container 10 can be managed by the temperature sensor T. The temperature sensor T may be connected to the hot air generator so that hot air can be sent at a predetermined temperature.

An exhaust port 17 is opened at a position obliquely above the intake port 13, and a small exhaust fan 18 is provided immediately above the exhaust port 17. The hot air sent from the intake port 13 is drawn by the exhaust fan 18, passes through the environmental condition setting container 10, and is discharged from the exhaust port 17.

Further, the pressing means 60 is provided at the center position of the lid 16 so that stress can be applied to the specimen vertically downward from the upper surface side of the specimen storage container 20 installed in the environmental condition setting container 10. Opening 16a is provided.

The pressing means 60 includes an upper loading frame 61
A specimen pressing plate 63 is attached to the distal end of a shaft 62 that is lowered vertically downward. A load cell 40 a and a displacement meter 40 b are interposed as measuring means 40 between the shaft 62 and the loading frame 61.

The shaft 62 can be fixed by inserting the projecting lower end 62b of the guide bear link 62a into an opening provided at the center of the lid 16.

The specimen pressing plate 63 is formed to have a large thickness, and the front end of the shaft 62 is attached to the back side thereof. The specimen pressing plate 63 has a bottom surface 63a.
A porous member 64a is provided so as to be flush with the side. Further, a hole 64b is formed in the specimen pressing plate 63 so as to communicate with the back side of the porous member 64a, and an inner / outer communicating portion 64 is formed.

As described above, in the present shear strength testing apparatus, the intermediate principal stress (σ ₂ ) in the horizontal direction of the side surface of the specimen in the specimen storage container 20 is set to 0 (constraining the displacement), and the pressing means The stress can be applied to the specimen by operating the pressing means 60 and the pressing means 60 independently.

That is, the pressing means 60 is directed vertically downward.
Accordingly, the maximum principal stress (σ ₁ ) can be applied by the pressing means 50 in the horizontal direction, and the minimum principal stress (σ ₃ ) can be applied in the horizontal direction.

Further, the specimen is repeatedly dried and wet by hot air and wet and immersed by submersion to generate slaking, and under this condition, a plane strain shear test in which the uniaxial direction is constrained can be performed. .

(Embodiment 2) In this embodiment, a method of performing a plane strain shear test using the above-described shear test apparatus will be described.

To conduct a plane strain shear test, first,
The specimen storage container 20 is set in the substantially cylindrical environmental condition setting container 10. At the time of installation, environmental condition setting container 1
0, a side plate 23 is provided around a bottom 21 provided on the bottom 11.
a, 23a ', 23b and 23b' are screwed in the same manner as described in the first embodiment, and the specimen storage container 20 is assembled in a box shape with the upper part opened.

Further, when assembling the specimen storage container 20, the pressing means 50 and the displacement restraining means 30 from the side of the specimen storage container 20 are also attached. In the specimen storage container 20, the horizontal loading device 51 is moved so that the specimen pressing plate 53 can be pushed back and forth.
And the shaft 52 are connected. Similarly, the shaft 32 of the displacement restricting device 31 and the specimen restricting plate 33 are connected.

After assembling the specimen storage container 20 in this way, a soil investigation sample such as an embankment material is put in the specimen storage container 20. The soil investigation sample is further compacted in the specimen storage container 20.

For compaction, a compaction machine such as a rammer or a damper may be used. Also, the soil investigation sample is put into the specimen storage container 20 in a plurality of times,
Make sure to compact each time. Compaction is performed until a predetermined compaction degree or a predetermined density is reached. At the time of compaction, it is preferable that the inner wall surface of the specimen storage container 20 be thinly coated with grease or the like.

After the specimens are compacted in the specimen storage container 20 in this way, the specimen storage containers 20
The pressing means 60 is assembled on the upper side of. The specimen pressing plate 63 is placed on the specimen in the specimen storage container 20, and in this state, the tip side of the shaft 62 connected to the loading frame 61 vertically downward on the back side of the specimen pressing plate 63. Attach. As shown in FIG. 1, a load cell 40a and a displacement meter 40b are interposed between the loading frame 61 and the shaft 62 as the measuring means 40.

After assembling the specimen storage container 20 together with the pressing means 50 and 60 and the displacement restraining means 30 as described above, the specimen storage container 20 is adapted to the actual measurement ground environment and the like as shown in FIG.
As shown in ( ₂ ), the specimen restraint plate 33 of the displacement restraint means 30 is fixed (ε ₂ = 0). At the same time, the pressing means 50 applies the minimum principal stress (σ ₃ ) and the pressing means 60 applies the maximum principal stress (σ ₁ ) to the specimen.

The load acting on the specimen is applied to the displacement restraining means 3.
0, load cell 40a linked to pressing means 50, 60
And the displacement is measured by a displacement meter 40b linked to the pressing means 50 and 60. In this way, a stress according to the measurement conditions is applied to the specimen.

In this state, the air outlet 13 of the hot air generator (not shown) is connected to the air inlet 13 of the environmental condition setting container 10 in which the specimen storage container 20 is disposed by the heat insulating flexible pipe 14. Then, hot air of a predetermined temperature is sent into the environmental condition setting container 10.

By sending hot air of a predetermined temperature into the environment condition setting container 10 for a predetermined time, the environment condition setting container 10 is placed in a dry environment. As a result, the specimen in the specimen storage container 20 placed in the environmental condition setting container 10 comes into contact with the hot air through the inside / outside communication portions 22 and 64, and the moisture in the specimen is removed and dried.

After the specimen was dried in this state for a certain period of time, the hot air generator was removed from the connection nozzle 13a.
Instead, cover with lid 15.

Thereafter, the pipe connection port 12a of the water supply / drain port 12
A water supply pipe (not shown) is connected to the
Pour water into 0. The water may be introduced to such an extent that the specimen storage container 20 is submerged. By continuing the submerged state of the specimen storage container 20 for a certain period of time, the submerged environment (humidified environment) in the environmental condition setting container 10 can be exerted on the specimen through the internal and external communication portions 22 and 64. In this way,
Submerge the specimen until it becomes wet, then
The water is discharged from the water supply / drain opening 12.

By alternately repeating the drying means for sending hot air and the humidifying means for submersion in the above-described manner, the test specimen is repeatedly dried and wet to generate slaking.

At each stage of the repetition of the wet and dry operation, the load cell 40a and the measuring means 40 of the displacement meter 40b mutually intersect at right angles while the maximum principal stress (σ ₁ ) and the minimum principal stress (σ ₃ ) are kept constant. The amount of deformation in the direction of the pressing means,
The load in the direction of the displacement restraining means (the direction of the intermediate principal stress (σ ₂ )) is measured.

Further, while the minimum principal stress (σ ₃ ) is kept constant, only the vertical load, which is the maximum principal stress (σ ₁ ), is increased by the pressing means 60 to destroy the specimen and compress the plane strain. Testing can be performed.

At the same time, while the minimum principal stress (σ ₃ ) during the shearing is kept constant, the load in the maximum principal stress (σ ₁ ) direction and the maximum / minimum principal stress (σ ₁ , σ ₃ ) The amount of deformation of the specimen in the direction and the load in the direction of the intermediate principal stress (σ ₂ ) are measured.

Further, the minimum principal stress (σ ₃ ) of the specimen is
A similar test is performed instead of three or four types. The stress-strain curve determined at each minimum principal stress (σ ₃ ) can be used for deformation analysis.

Alternatively, the maximum deviation stress (σ ₃ · σ ₃ ) max at each minimum principal stress (σ ₃ ) is expressed as a Mohr stress circle, and these stress circles are linearly approximated to obtain a strength parameter (adhesive strength). And internal friction angle).

(Embodiment 3) In Embodiment 1 described above,
As shown in FIG.
Although the apparatus is configured as a plane strain shear strength test apparatus in which displacement in one axial direction is restricted, a configuration in which a pressing means 70 is provided instead of the displacement restricting means 30 is also conceivable.

As shown in FIG. 5, such a shear strength test apparatus is provided so that a shaft 72 can be pressed in a horizontal direction with a load cell 40a and a displacement meter 40b interposed in a hydraulically operated cylinder 71. The shaft 72 is guided by a guide bearing 72a, and a test piece pressing plate 73 is provided on the tip side of the shaft 72 via a support plate 73a.

The specimen pressing plate 73 is smaller than the specimen pressing plate 53, and the main stress (σ ₂ ) applied by the pressing means 70 is smaller than the stress (σ ₃ ) applied by the pressing means 50. It is configured to be large.

By using the shear strength test apparatus thus configured, the principal stress σ ₁ > σ ₂ > σ ₃ is satisfied.
A main stress test (triaxial shear strength test) can be performed.

In particular, in the first and third embodiments, the pressing means 50, 60, 70 and the displacement restraining means 30
Since the assembling function is appropriately configured in the environmental condition setting container 10 and the specimen storage container 20, it can be easily switched to a plane shear strength test device or a three principal stress test device as appropriate.

Further, in the configuration of the shear test apparatus described in the first embodiment, if the pressing means 50 is replaced by the displacement restraining means 30, the apparatus can be configured as a compression settling test apparatus.

Although the invention made by the inventor has been specifically described based on the embodiment, the invention is not limited to the above-described embodiment and can be variously modified without departing from the gist of the invention. Needless to say, there is.

[0089]

Advantageous effects obtained by typical ones of the inventions disclosed in the present application will be briefly described.
It is as follows.

(1). In the configuration of the present invention, mudstone, shale,
The maximum principal stress (σ) in the specimen containment vessel was prepared by compacting the embankment material consisting of soft rocks such as tuff and sandstone.
₁ ) and the minimum principal stress (σ ₃ ) can be applied independently to each other, so the shear strength test is performed in a state that can reproduce the stress state on the slope caused by embankment creation and the high overburden pressure state in the embankment. be able to.

(2). In the configuration of the present invention, the specimen storage container provided with the internal / external communication part is installed in the environment condition setting container in which the drying environment and the humidifying environment can be set alternately. To generate slaking.

(3). As a drying means, a means for sending hot air of a predetermined temperature by a hot air generator into a container for drying for a certain period of time is employed, and as a humidifying means, a means for supplying water into the container and submerging the specimen storage container is adopted. Slaking can be generated with a simple configuration.

(4). In the configuration of the present invention, since the slaking is generated in a state where the specimen is placed in the specimen storage container provided with the pressing means, only the maximum main stress of the specimen is continuously generated after the slaking is generated in the specimen. For example, the soil strength test in the slaking state can be performed without replacing the specimen with another container or the like by increasing the number of samples.

(5). For this reason, it is possible to accurately evaluate the stability of the embankment slope by soft rock material in which slaking is likely to occur, and accurately predict settlement of the embankment.

(6). In the shear strength test apparatus of the present invention, the specimen is restrained from displacement in the direction of the intermediate principal stress (σ ₂ ) (ε
₍₂ = 0), the maximum principal stress (σ ₁ ) and the minimum principal stress (σ ₃ ) are independently applied, so that the test can be performed in a plane strain compression state closer to the condition of the original position.

(7). In the shear strength test apparatus of the present invention, since the pressing means can be provided instead of the displacement restraining means in the intermediate main stress direction, the maximum, intermediate, and minimum main stresses (σ ₁ , σ ₂ , σ ₃ ) are respectively determined. Independently controlled three principal stress tests (σ ₁ > σ ₂ > σ ₃ ) are possible.

(8). In the shear strength test apparatus according to the present invention, the horizontal two of the intermediate principal stress (σ ₂ ) and the minimum principal stress (σ ₃ )
If a test in which only the maximum principal stress (σ ₁ ) is applied while restraining each displacement in the direction is performed, a normal compression settlement test is also possible.

[Brief description of the drawings]

FIG. 1 is a sectional view of a shear strength test apparatus according to the present invention.

FIG. 2 is a plan sectional view of the shear strength test apparatus of the present invention.

FIG. 3 is a cross-sectional view of a main part showing a connection state between side plates according to the present embodiment.

FIG. 4 is an explanatory view showing the direction of stress applied to a specimen.

FIG. 5 is a plan cross-sectional view of a shear strength test apparatus capable of performing a triaxial shear strength test according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Environmental condition setting container 11 Bottom part 12 Supply / drain port 12a Pipe connection port 13 Intake port 13a Connection nozzle 14 Insulated flexible pipe 15 Lid 16 Lid 16a Opening 17 Exhaust port 18 Exhaust fan 20 Specimen storage container 21 Bottom 22 Inside and outside Communication part 22a Porous member 22b Through hole 23a Side plate 23a 'Side plate 23b Side plate 23b' Side plate 24a Side plate 24b Opening 30 Displacement restraint means 31 Displacement restraint device 32 Shaft 32a Guide bearing 33 Specimen restraint plate 33a Support plate 40 Measurement means 40a Load cell 40b Displacement gauge 50 Pressing means 51 Horizontal loading device 52 Shaft 52a Guide bearing 53 Specimen pressing plate 53a Support plate 60 Pressing means 61 Loading frame 62 Shaft 62a Guide bearing 63 Specimen pressing plate 64 Passing portion 64a Porous member 64b Hole 70 Pressing means 71 Loading device 72 Shaft 72a Guide bearing 73 Specimen pressing plate 73a Support plate

Claims (5)

[Claims] 1. A shear strength test device for performing a shear strength test of soil under conditions of occurrence of slaking, wherein a stress is independently applied to a sample of an internal soil investigation sample from three axial directions orthogonal to each other by a pressing means. A storage container to be provided, and an environment condition setting container capable of alternately placing the storage container installed therein in a dry environment and a humid environment by both drying means and humidifying means. The specimen storage container installed in the environment condition setting container, and an internal / external communication part for providing an environmental condition in the environmental condition setting container to the test object in the specimen storage container is provided, A shear strength test apparatus characterized in that a measuring means is provided in conjunction with a pressing means. 2. The shear strength test apparatus according to claim 1, wherein the drying means passes hot air through the environmental condition setting container to dry the specimen storage container installed in the environmental condition setting container. Means for placing in an environment, wherein the specimen in the specimen storage container placed in the dry environment is made to be in a dry state through the inside / outside communication part, and the humidifying means is the environmental condition Means for pouring water into the setting container until the specimen storage container is submerged, and placing the specimen storage container in a humidified environment, wherein the specimen in the specimen storage container placed in the humidified environment is A shear strength test apparatus wherein a specimen is brought into a wet state via the inside / outside communication part. 3. The shear strength test apparatus according to claim 1, wherein one of the pressing means in two horizontal directions orthogonal to each other is replaced with a displacement restraining means. Shear strength test equipment. 4. A shear strength test method for performing a shear strength test of soil under conditions of occurrence of slaking, wherein a soil investigation sample is placed in a specimen storage container that can be pressed independently from three axes perpendicular to each other. Inserting and compacting the specimen, applying a stress by pressing the specimen from the three axial directions according to the measurement conditions, and alternately placing the specimen in a dry state and a wet state hand,
A shear strength test comprising: a step of generating slaking on the specimen; and a step of applying a stress to the specimen in a state where the slaking occurs by the pressing means to cause the specimen to shear and break to obtain triaxial shear strength. Method. 5. A shear strength test method for measuring shear strength of soil under conditions of occurrence of slaking, wherein one of two horizontal directions among three axial directions orthogonal to each other can be restrained by displacement restraining means. A step of putting a soil investigation sample into a specimen storage container which can be independently pressed by a pressing means from two axial directions to form a specimen by compaction, and measuring conditions for the specimen from the two axial directions. Applying a stress by pressing together, the test specimen, alternately placed in a dry state and a wet state,
A shear strength test comprising: a step of generating slaking on the test specimen; and a step of applying a stress to the test specimen in the state of occurrence of slaking to cause the test specimen to shear and break to obtain plane strain shear strength. Method.